When I press render, my object changes
You probably have keyframes set for your objects. If you have set a keyframe for an object and then you move it without overwriting the keyframe, the animated property gets reset on render.  

To fix this issue move the object into the desired position and press I. Select LocRotScale to set the location, the rotation and the scale.  

When you render the scene now, there should be no more problems with moving objects.